Laminates of composite materials are often used in the construction of rotor blades for helicopters, fixed wing aircraft, and wind turbines. In a laminate, mutually bondable composite layers are stacked on top of one another, and the stacked layers are cured such that adjacent layers are bonded together.
Most rotor blades employ composite laminate skins or a shell over an internal structure such as a blade spar that extends along a length of the rotor blade toward a tip thereof. The skin or shell of the rotor blade is generally built around the internal structure of the blade by stacking layers of fiber fabrics in a half mold. Historically, these layers of fabrics have been pre-impregnated with a curable thermoset resin. The internal structure of the blade (including the spar) is placed on the stacked fabrics. A suitable filling mass such as foam or balsa may also be placed on the stacked fabrics around the internal structure. More layers of fabrics are folded onto the internal structure (and the filling mass, if any) and a second half mold is placed on the first half mold. The curable resin is then polymerized by the addition of heat and pressure to the mold, thereby forming the rotor blade.